The present invention relates to a bicycle rear derailleur shifting controller, and more particularly to a simple structure of bicycle rear derailleur shifting controller which positively axially moves the derailleur cable to accurately shift the rear derailleur mechanism of the bicycle when rotated.
A regular bicycle rear derailleur shifting controller is generally comprised of a base and a rotary knob. The base comprises a coupling tube coupled to the handlebar of the bicycle. The rotary knob is fastened to an endpiece at one end of the derailleur cable, and rotatably coupled to the coupling tube of the base. Further, an arcuate spring member and a detent section are respectively provided at the base and the rotary knob. The arcuate spring member comprises an indexing projection shifted between notches at the detent section. The derailleur cable is driven to shift the rear derailleur mechanism of the bicycle upon rotary motion of the rotary knob. This structure of bicycle rear derailleur shifting controller is not satisfactory in function. Because the derailleur cable is wound round the coupling tube of the base and turned radially with the rotary knob around the coupling tube, it tends to be hindered by internal structure of the base, causing the rear derailleur mechanism shifting operated unable to be accurately achieved.